Selection of site
The area needs to be sufficiently isolated to ensure that there is no possibility of any pollutants or contaminants flowing or drifting into it from any known or unknown sources. There should be a buffer zone on sufficient width on all sides of the plot depending on the topography of the area, to ensure the above safety. The minimum width of buffer zone should be 100 m. The minimum depth of soil profile should be 1.5 to 2.0 m and organic matter status should be medium to high level depending on the elevation and rainfall of the area. A perennial source of water free from pollutants is required in the estate for large scale compost preparation, which is essential for organic tea cultivation. A detailed history of a period of about ten years, fully documented to give details of external inputs during pre-conversion period, should be maintained to facilitate inspection of organic tea cultivation.
The minimum conversion period should be three years from the last usage of synthetic agrochemicals. One can start marketing the tea as “in conversion organic tea” only after the lapse of one year from the start of conversion. Tea can be marketed as “organic tea” only after the completion of conversion of three years.
Soil water conservation measures
Adoption of proper soil and water conservation measures is essential for organic tea cultivation. Trenching and mulching conserve rain water and make the moisture available to the plants on a sustained basis. Tea pruning, leaf litter and compost should be buried in trenches. Mulching can be done with Guatemala grass (Tripsacum laxum), weeping love grass (Eragrostis curvula), bracken fern, shade tree loppings and other plant materials. Guatemala grass can be planted in large vacant patches with the twin objectives of rehabilitating the soil raising mulch material.
On organic cultivations, no gen-manipulated varieties are allowed.Tea plants are propagated both generatively or vegetatively. Cultivation takes place under controlled conditions in special beds over the space of 2–3 years. It is recommended to establish own nurseries in the tea garden, in order to ensure a continuous supply of untreated and healthy plants. In choosing locations for the nursery, the following should be considered:
•A protected site
•Sufficient supply of water
•A site that has not been cultivated, if possible (virgin soil)
•Preparation of the site with legumes (1-2 years, e.g. with Crotalaria ssp., Tephrosia candida, that are afterwards mulched)
• Natural shade (e.g. Tephrosia candida, Crotalaria ssp., Sesbania ssp.)
When establishing a new tea plantation, care should be taken to manually uproot problematical grasses, such as e.g. Imperata cylindrica. Subsequently, it is recommended to plant fast growing covering plants like Mimosa pudica, Guatemala grass (Tripsacum laxum), to suppress the growth of unwanted species of flora. Between 10,000 and 20,000 plants per hectare can be planted, depending on the gaps between rows and plants. The crop density should always be adapted to the site conditions (slope, altitude, micro-climate etc.), as well as incorporating those shading trees necessary on organically cultivated tea plantations. Shade trees have a great importance to the organic cultivation of tea.
The following is a list of their positive effects:
• Nutrient supply (e.g. nitrogen, when legume shading trees are used; they retrieve nutrients from lower soil levels; reduction of nutrient losses from washing out)
- Build-up of humus
• Protect the tea bushes from too much sun (yield reductions are possible when the solar radiation is too intense, and there is a lack of shade)
• Reduction of erosion through wind and rain (and damage from hail)
• Positive micro-climatic effects e.g. during drought periods
• Encourage benefical insects to settle
When choosing tree varieties to use as shade trees, it is important to use plenty of local, adapted varieties, enough leguminous trees, and overall, a wide variety of differing species. Care should be taken to choose fast, and not so fast growing varieties of shade trees at the beginning of cultivation.The correct combination of shade tree varieties should always be based on local experience, or, in certain cases, tried out on site. As regards the number of shade trees or the intensity of shade required, the following rule can be used as a guide: The higher the tea garden is located, the less shade is necessary (and also the other way round).